This invention relates to the plating of magnetic media, and more specifically to a process utilizing an electroplating process for the deposition of a thin magnetic layer.
Most currently available plated media, used as magnetic disks for mass storage in data processing, are produced by totally electroless processes. The main problem with such plated media is that their performance is limited by noise problems arising from the electro-magnetic characteristics of the plated layers. The noise problems are created within the magnetic layer by the electroless processes. These processes produce non-uniform layers by forming uneven crystalline structures, by including contaminants in the layer, and by forming occasional plating voids. Each of these plating phenomena will contribute to noise in high density memory devices. This problem is particularly acute in high performance applications, where higher storage densities are required.
A known process to reduce the noise problem utilizes electroplated media. It starts with an heat-treatable alloy, such as the 7075 type available from Alcoa Aluminum, which is then anodized to provide a smooth adhesion surface. A layer of copper is deposited on the anodized surface by electroplating and is then polished. A layer of nickel-cobalt (NiCo) is electroplated over the now smooth copper layer and is then exposed to some temperature for a period of time sufficient to produce an oxidation layer. For example it may be exposed to a temperature range of 580.degree. to 680.degree. F. for approximately an hour. The main problem with this process is that it depends on a non-standard heat-treatable aluminum alloy substrate that can be easily anodized. Such a substrate, although commercially available, is a non-standard item and is very expensive.